The long-term purpose of this proposal is directed toward a better understanding of suprathreshold auditory behavior among normal listeners and patients with sensorineural hearing loss. Three specific areas of investigation are described. In the first program, a thorough comparison will be made among three procedures for obtaining frequency-gain and saturation sound pressure level characteristics of amplification systems, one an experimental method that evolved from our investigation and two other methods representing the selective amplification and fixed frequency gain approaches. A second project area is directed toward elucidating specific psycho-acoustic dysfunctions that result in difficulties encountered by hearing impaired individuals in processing speech stimuli. The relations among frequency selectivity, temporal processing and speech discrimination will be studied in these experiments. In a final project area, the research will be directed at testing the "edge effect" hypothesis. Specifically the effects of notch depth and rejection rate on the detectability of tonal signals will be examined.